The Girls Aloud beauty - who has starred in the 'St. Trinians' movies - narrowly missed out on the role of Emma Frost to actress January Jones in the superhero action prequel, but is thrilled she got so far.
She said: "I got called back three times for 'X-Men' but I missed out on the part to January Jones which was fine, she's a more established actress, but I was pleased to have got that far down the line."
Sarah has been offered several roles recently, but plans to wait until a more powerful part comes up.
'X-Men: First Class' started filming last month, and tells the tale of the early relationship between Charles Xavier and Erik Lehnsherr, features an all star cast including Nicholas Hoult, James McAvoy, Jennifer Lawrence, Michael Fassbender and Kevin Bacon.